Increasing the melting point of polymerized rosin



Patented Apr. 3, 1951 INCREASING THE MELTING'POIN T OF POLYMERIZED ROSINKenneth C. Laughlin, Wilmington, Delz, assignor to Hercules PowderCompany, Wilmington, 1101., a corporation of Delaware No Drawing.Application August 18, 1949, Serial No. 111,099

This invention relates to the fractionation of polymerized rosin andmore particularly to a method for the separation of a fraction ofincreased melting point from polymerized rosin.

8 Claims. (Cl. 26099.5)

clave fitted with a stirrer. The mixture was agitated at 99i5 C. for 30minutes and then allowed to settle for 30 minutes so that the insolublefraction could settle out as the lower phase.

polymerized rosin with a liquefied normally gaseous hydrocarbon havingat least three carbon atoms, at a temperature within the range of about50 C. and approximately the critical temperature of the hydrocarbon, andseparating the portion insoluble in said hydrocarbon as a polymerizedrosin of increased meiting point;

The process of this invention is illustrated by the following examplesin which all parts are parts by weight unless otherwise stated. Allmelting points were obtained by the Hercules drop method.

Example 1 T 903 parts pulverized polymerized rosin melting point by dropmethod 100 C., acid number 151) 'was added 54%8 parts propane in anauto- ,in the extraction process will vary with the par- It is known tofractionate polymerized rosin by The lower phase then was withdrawn andfreed means of selective solvents and to separate a of occluded propaneby distillation of the solvent... fraction having less tendency, tocrystallize. The This fraction amounted to 87.2% of the original processleaves much to be desired, however, as far polymerized rosin. It had amelting point of as the production of a polymerized rosin of in- 106 C.and an acid number of 1541. The upper creased melting point isconcerned. It is also phase yielded on distilling off thesolventaviscous known to obtain a polymerized rosin of higher liquid.state of polymerization by distilling off the oils A series of exampleswere carried out following and unpolymerized resin to recover as theresidue the general procedure of Example 1. The data a dark-coloredpolymerized rosin of higher meltobtained on these examples are tabulatedin ing point. Such a product is of reduced acid Table I. In Example 3the polymerized rosin" number due to partial decarboxylation during theused was the polymerizedrosin obtained as the distillation process. Thisproduct, while higher upper phase of Example 2. i It was thuspolymermelting in contrast to that of the product of the ized rosinwhich had already been freed of part of selective solvent process, isunsatisfactory for its high melting constituents. The combination manyuses because of its dark color and reduced of Examples 2 and 3.thusexemplifies a stepwise acid number. fractionation. In Example 5, thepolymerized Now in accordance withthis invention, it has rosin treatedwas the higher melting polymerized been found that a polymerized rosinfraction, rosin obtained from the lower phase of Example melting higherthan the polymerized rosin from .4. The combination of Exa p and 5eXemwhich it is obtained, is produced by extracting a '25 .plifiesanother stepwise purification procedure.

Table I Example 1. 1 2 3 4 5 o 7 Polymerized Rosin (Weight) 908 1,816181 300 194 1,348 750 Melting Point, 0 100 100 72 131 10 12.5 AcidNumber 151 151 127 151 155 Propane (Weight) 5,448 5,448 1,588 5,448 2,270 Butane (Weight) 5,448 3,632 Fractionation Temperature, *0 90 50 5050 14 Upper Phwe per cent. 12.8 20.3 16.8 81 22.5 Acid Number 127 124146 105 159 Melting Point, 72 57 -92 199 Lower Phase 79.7 19-25 7 77.58.1 cid Numbez 154 148 149-155 153 159 149 Melting Point, c 106 113 99131. 141 109 14s The ratio of solvent to polymerized rosin used ticularnormally gaseous hydrocarbon used and the degree of polymerization ofthe rosin. The solubility of the polymerized rosin increases withincreasing molecular weight of the hydrocarbon .and the ratio will,therefore, not be the same for all hydrocarbons.

normally gaseous hydrocarbon solvent per part polymerized rosin isnecessary to obtain effective separation and to avoid the solubilizingeifects of the polymerized rosin constituents. Not more than about 20parts normally gaseous hydrocarbon solvent per partpolymerized rosinwill norilifi'm'ally be used since yields becom too low for At leastabout three parts economical operation when a large excess of solvent isused.

The normally gaseous hydrocarbons useful in the fractionation processinclude propane, normaland isobutanes and the normally gaseous pentanes.These may be used in pure form or in mixtures. The preferred hydrocarbonis propane but it may be used in admixture with butane, or thepolymerized rosin may be dissolved in butane and propane addedsubsequently.

The polymerized rosins which may be fractionated by extraction with anormally gaseous liquefied hydrocarbon are made by treating a naturalwood or gum rosin or tall oil rosin with a polymerizing agent such asvolatile metal halides, as boron trifluoride, zinc chloride, stannicchloride, aluminum chloride, ferric chloride;

mineral acids, as sulfuric acid, phosphoric acid;

fullers earth; hydrogen fluoride; acid salts, as sodium acid sulfate,etc.; hydrofiuoroboric acid; etc., according to methods known to theart.

Although the process of this invention may be carried out on anypolymerized rosin, it is preferahly applied to those polymerized rosinshaving a drop melting point of at least 100 0., since it is particularlysuitable for the production of polymerized rosin of melting pointshigher than is readily attainable by commercial methods.

The extraction process is preferably carried out on poiymerized rosin ina dispersed state such as in powder form, or in the form of a fluiddisper"ed as droplets and the like. However, with polymerized rosinwhich tends to be gummy and not readily dispersible at extractiontemperatures, the process is equally operable using a mixer of properdesign. Simple propeller-type mixers are satisfactory for the readilydispersed polymerized rosins, and mixer giving a folding or kneadingtype of action are satisfactory where the polymerized rosin formsviscous, gummy, or doughlike mixtures with the liquefied normallygaseous hydrocarbon. Likewise, the process may be carried out onpolymerized rosin rendered fluid and dispersible by a normally liquidvolatile hydrocarbon such as pentanes, heptanes, gasoline, kerosene,benzene, toluene, or cymene. The volatile hydrocarbon can be distilledoff for recovery of the nonvolatile residue extracted from thepolymerized rosin.

The solubility of the components of polymerized rosin decreases withincrease in temperature for the normally gaseous hydrocarbons and thesolubility decreases more rapidly as the critical temperature isapproached. Moreover, at the critical temperature, there is lessdifference in solubility of the polymerized and unpolymerized acids ofthe polymerized rosin but there is a large difference in solubilitybetween the oils and the acid constituents. The oils may, therefore, beseparated from the acid constituents by eifecting the extractionsubstantially at the critical temperature. At temperatures below thecritical temperature, unpolymerized rosin acids are extracted from thepolymerized rosin acids, the degree of solubility of the unpolymerizedrosin acids depending on the temperature. At temperatures within therange of about 50 C. and to 20 below the critical temperature, thegreatest difference in solubility between the polyn erized andunpolymerized rosins obtains. To obtain a polymerized rosin of increasedmelting point by extraction of a fraction containing chiefly the oilsand neutral constituents, the extraction is carried out substantially atthe critical temperature but above about 50 C.

The polymerized rosins of increased melting point made by the process ofthis invention may be subjected to any desirable subsequent treatment.Thus, for example, they may be subjected to refining treatments if it isdesired to improve their color. The polymerized rosin may thus bedissolved in a high-boiling hydrocarbon solvent such as gasoline orkerosene and be treated with selective solvents for removal of the colorbodies. Likewise, a solution of the polymerized rosin of this inventionmay be refined by means of adsorbents such as adsorbent earths.

What I, claim and desire to protect by Letters Patent is: 1

l. The process of fractionating polymerized resin which comprisesextracting the polymerized rosin with a liquefied normally gaseoushydrocarben having at least three carbon atoms, at a temperature withinthe range of about 50 C. and approximately the critical temperature ofthe hydrocarbon, and separating the portion insoluble in saidhydrocarbon as a polymerized rosin of increased melting point.

2. The process of fractionating polymerized resin which comprises mixinga dispersion of the polymerized rosin in a liquefied normally gaseoushydrocarbon having at least three carbon atoms, at approximately thecritical temperature of the hydrocarbon until partial dissolution ieffected, separating the resulting hydrocarbon solution, mixing theresidual polymerized rosin with another portion of liquefied normallygaseous hydrocarbon at a temperature within the range of about 50 C. anda temperature substantially less than the critical temperature of thehydrocarbon until partial dissolution of the polymerized rosin iseffected and separating the insoluble portion as a polymerized rosin ofincreased melting point.

3. The process fractionating polymerized rosin which comprises mixingthe polymerized rosin with liquefied propane at a temperature within therange of about 50 C. and approximately the critical temperature of thehydrocarbon until partial dissolution is effected and separating theinsoluble portion as a polymerized rosin of increased melting point.

e. The process of fractionating polymerized rosin which comprises mixingthe polymerized rosin in liquefied propane at a temperature within therange of about 50 C. and approximately the critical temperature of thehydrocarbon until partial dissolution is effected and separating theinsoluble portion as a polymerized rosin of increased melting point.

5. The process of fractionating polymerized rosin which comprises mixingthe polymerized rosin in liquefied propane at a polymerize-d resin topropane ratio within the range of 1:3 and 1:20

at a temperature within the range of about 50 C. and approximately thecritical temperature of the propane until partial dissolution iseffected and separating the insoluble portion as a polymerized rosin ofincreased melting point.

6. The process of fractionating polymerized rosin which comprises mixingthe polymerized 5 rosin with liquefied butane at a temperature withinthe range of about 50 C. and approximately the critical temperature ofthe hydrocarbon until partial dissolutionis effected and.

separating the insoluble portion as a polymerized rosin of increasedmelting point.

7. The process of fractionating' polymerized rosin which comprisesmixing the polymerized rosin in liquefied butane at a temperature withinthe range of about 50 C. and approximately the critical temperature ofthe hydrocarbon until partial dissolution is effected and separating theinsoluble portion as a polymerized rosin of increased melting point.

8. The process of fractionating polymerized rosin which comprises mixingthe polymerized rosin in liquefied butane at a polymerized rosin 6 V cto butane ratio within the range of 1:3 and 1:26 at a temperature withinthe range of about 50 C. and approximately the critical temperature ofthe butane until partial dissolution is effected and separating theinsoluble portion as a polymerized rosin of increased melting point.

KENNETH C. LAUGHLIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,806,973 Humphrey May 26, 19312,142,592 Waligora Jan. 3, 1939 2,310,374 Rummelsburg Feb. 9, 1943

1. THE PROCESS OF FRACTIONATING POLYMERIZED ROSIN WHICH COMPRISESEXTRACTING THE POLYMERIZED ROSIN WITH A LIQUEFIED NORMALLY GASEOUSHYDROCARBON HAVING AT LEAST THREE CARBON ATOMS, AT A TEMPERATURE WITHINTHE RANGE OF ABOUT 50* C. AND APPROXIMATELY THE CRITICAL TEMPERATURE OFTHE HYDROCARBON, AND SEPARATING THE PORTION INSOLUBLE IN SAIDHYDROCARBON AS A POLYMERIZED ROSIN OF INCREASED MELTING POINT.